Serpentine belt noise

[Ron41]

Hi all, a few weeks ago I had a very sweaky serpentine belt which I have replaced and also put 2 new idley pulleys on as the bearings were shot in them, that got rid of the sweaky belt problem but I have noticed when I first start the car, I get like what sounds like a light rattling metal sound thats only present for about 3 - 4 minutes upon startup, once the motor is warmed up it runs fine, no noise at all.
I have checked all pulleys they sound fine and all nuts are tight, took off the belt a couple of times and refitted it, thought I may had installed it right but it looks fine.
I thought maybe the tensioner pulley but that is hard to move, but does sweak when pulling it down to fit the belt.
I took off the belt and started it up for a minute, no noise at all, any ideas guys,
thanks
Rony

[POVRTY]

belt tensioner?

[SV62NV]

i also started hearing that type of sound in my car when i first started it and did some searching...

the problem was i had less than a litre of oil in my engine

note to self: change oil every 10000km not every 20000km lol

but it could be a different situation with you as you mentioned it could be belt tensioner

[vsl67]

I have a similar rattle are start up but its the cat ,Have you tried starting the car with the belt off so you know for sure its one of the bolt on acessaries and not something else?

[tt460]

Sounds like a bearing to me, i would spray some wd40 onto a pulley start the car and see if its there. Do one pulley at a time to try and work out what one it is, just remember you are treating the symptom not the problem

[S2_VR_]

i have just spent the arvo changing my pulley's........turns out its the Altenator Bearings (they are a bit dry). i am about to pull them out and change them...or grease them up....but it sounds like the same thing...

[lyndon_breeze]

maybe the pulleys have been on the self to long, or runners for the bearings has dirt or little dent in it, like when a cv joint is knocking

[Ron41]

Thanks everyone for your replies, I have spun all the pulleys around including the alternator and they are all fine since replacing the 2 idley pulleys, took the belt off and started the car for a minute and no noise at all, so I am still swaying towards the tensioner pulley as it is the original one, since I have had the car since it was only 12 months old.
The strange part is the tensioner pulley is hard to pull down when replacing the belt, it is not weak as you would expect, but does sweak when moving it down.

thanks again guys.